fix(pool): prevent writing to closed worker

packages/vitest/src/node/pools/pool.ts

@@ -76,8 +76,9 @@ export class Pool {
       const activeTask = { task, resolver, method, cancelTask }
       this.activeTasks.push(activeTask)
 
+      // active tasks receive cancel signal and shut down gracefully
       async function cancelTask() {
-        await runner.stop()
+        await runner.waitForTerminated
         resolver.reject(new Error('Cancelled'))
       }
 

packages/vitest/src/node/pools/poolRunner.ts

@@ -30,6 +30,7 @@ export class PoolRunner {
 
   private _state: RunnerState = RunnerState.IDLE
   private _operationLock: DeferPromise<void> | null = null
+  private _terminatePromise: DeferPromise<void> = createDefer()
 
   private _eventEmitter: EventEmitter<{
     message: [WorkerResponse]
@@ -44,6 +45,10 @@ export class PoolRunner {
     return this._state === RunnerState.STOPPED
   }
 
+  public get waitForTerminated(): Promise<void> {
+    return this._terminatePromise
+  }
+
   public get isStarted(): boolean {
     return this._state === RunnerState.STARTED
   }
@@ -58,7 +63,11 @@ export class PoolRunner {
       }),
       {
         eventNames: ['onCancel'],
-        post: request => this.postMessage(request),
+        post: (request) => {
+          if (this._state !== RunnerState.STOPPING && this._state !== RunnerState.STOPPED) {
+            this.postMessage(request)
+          }
+        },
         on: callback => this._eventEmitter.on('rpc', callback),
         timeout: -1,
       },
@@ -199,6 +208,7 @@ export class PoolRunner {
     finally {
       this._operationLock.resolve()
       this._operationLock = null
+      this._terminatePromise.resolve()
     }
   }